Rental vehicles are typically operated for a pre-determined period of time, such as one or two years, and then disposed of by being auctioned or offered to the public at special sales. These vehicles will be withdrawn from rental service and prepared for sale. Part of this preparation is to empty their fuel tanks. These tanks normally have a significant amount of fuel in them. This is particularly true of vehicles that are withdrawn from active use after their last scheduled run, which may have been short, but which started the run with a full tank.
Fuel removal has been a problem for this industry. The task has been handled by providing a mobile pumping unit that withdraws the fuel from the tanks of the vehicles, and, when this task is complete, or the tank of the recovery vehicle is full, the fuel is disposed of by returning it to one of the bulk storage tanks connected with the facility's fuel-dispensing equipment. These facilities usually do not have any means of measuring the quantity of fuel so recovered and returned to the system. Further, they have no means of providing a record of how much fuel is recovered from any particular vehicle or any record of the total amount of fuel that is so recovered. This is important information, particularly in ascertaining the profitability or lack of profitability of the car rental operation.
Also, modern vehicles have rollover valves, designed to keep the filler neck of the fuel tank shut unless opened by a fuel nozzle or by the weight of a column of fuel. Thus, it is necessary to also defeat or bypass the rollover valve to remove fuel from the fuel tank.